Alternatively titled ‘Cold-Case CSI: Roman Syria AD256’, this is a detective story, an exercise in uncovering forgotten secrets of a ferocious battle fought between the Romans and Sasanians. It is a tale told entirely through archaeology, for the siege in which perished the city of Dura-Europos, ‘Pompeii of the East’, is unknown to history. The Franco-American excavations of the 1920s-30s, and new work between 1986-2011, has revealed in graphic detail the course of the Sasanian attacks, and the determined efforts of the Roman defenders to thwart them; siege ramps and mines are still there to be seen, and excavation recovered copious weaponry and the bones of the slain, including dramatic traces of the defenders’ last stand. This, the most vivid archaeological testimony ever found for ancient warfare, is still revealing surprises. For careful reappraisal of evidence preserved in the old excavation archives suggests that an early form of chemical warfare was among the horrors unleashed at Dura, the earliest archaeological testimony for one of the grimmest of all facets of human conflict…